lost my Administrative purposes on my computer

Password reset using the built-in administrator account (in Safe Mode)

* Press F8 when the system is booting up;
* Choose Safe Mode from the list of additional Windows boot options;
* Pick the built-in Administrator account, which is not password-protected by default (you may pick any user of the Administrators group whose account is not password-protected or whose password is known to you);
* When a dialog window pops up notifying you that Windows is working in the Safe Mode choose Yes;
* Proceed to Start -> Control Panel -> User Accounts;
* Click on the icon representing the account whose password you intend to reset;
* Choose Change Password in the menu on the left;
* When prompted, either provide a new password or leave the fields empty (to reset the password);
* Press Change Password;
* Close the User Accounts window;
* Close the Control Panel;
* Reboot your computer.